1. Field of the Invention
The present invention relates to a sealing and protective cap for grease fittings and more particularly, but not by way of limitation, to a cap for sealing the port of a button-head grease fitting.
2. Background of the Invention
Throughout the industry there is equipment and machinery which requires internal lubrication, the lubrication being applied by way of grease zerts or fittings. Many such devices operate with high internal pressures such as valves, pumps and the like wherein the grease or lubrication fittings contain a check valve to maintain internal pressure.
To perform lubrication, one must force lubrication through the fittings with sufficient pressure to overcome the resistance of the check valve and the internal pressure, such lubrication being typically accomplished by way of a grease gun.
A typical grease fitting containing the check valve that is used in such application is the "button-head" grease fitting which is simply a hollow bolt like device having threaded shank which is threadably disposed in the port in the device requiring lubrication. The outer face of which contains a grease introduction port and a spring loaded check valve.
To apply lubrication, a grease gun is attached to the button-head portion of the fitting and the lubrication is injected with a force to overcome the spring of the check valve and the internal pressure of the device being lubricated.
Either through corrosion, deterioration of seals or the presence of foreign matter, the lubrication fitting will, over a period of time, develop a tendency to leak around the check valve through the grease introduction port.
In most instances, such a leak is unacceptable, and many times due to economics or even safety considerations, to shut down and replace the lubrication fitting is also unacceptable.